JP2013125229A - Lens barrel and imaging apparatus - Google Patents

Abstract

Provided is a lens barrel capable of adjusting a position of a lens frame with a simple structure and suppressing a space necessary for the position adjustment.
A lens barrel that adjusts the position of an adjustment lens included in a plurality of lenses of an optical system in the optical axis direction with respect to another lens is provided. This lens barrel includes a lens frame 1 that holds an adjustment lens, and a base frame 2 that holds the lens frame 1 in an adjustable manner. The lens frame 1 includes a first adjustment step surface having a plurality of adjustment surfaces provided at different heights adjacent to the rotation direction of the lens frame 1, and a second adjustment step surface. The second adjustment step surface is provided at a 180-degree rotation phase position from the position where the first adjustment step surface is provided. The base frame 2 includes a support surface that comes into contact with the first adjustment step surface 11 and the second adjustment step surface 12.
[Selection] Figure 1

Description

  The present invention relates to a lens barrel and an imaging apparatus.

  In recent years, imaging devices such as cameras and video cameras have been increasing in magnification and size. In order to realize a high magnification of the imaging apparatus, the diameter of the lens itself included in the imaging apparatus is increasing. In addition, as the size of the image pickup apparatus advances, the lens position accuracy has been improved in order to satisfy the optical performance.

  The optical performance of the image pickup apparatus cannot be satisfied only by improving the accuracy and lens performance of the components constituting the lens barrel, and therefore it is necessary to adjust the lens position according to the individual lens barrel. For example, eccentric adjustment that aligns the lens axis, inclination adjustment that adjusts the inclination of the lens axis, or tracking adjustment that adjusts the distance between adjacent lenses has been proposed.

  Patent Document 1 discloses a method for adjusting the movement of a lens in a lens barrel having a lens frame in which three sets of adjustment step surfaces are formed stepwise in the circumferential direction. In this movement adjustment method, the height of the optical axis direction is adjusted by changing the adjustment step surface to be brought into contact with the holding member by rotating the lens frame.

JP 2009-237409 A

  The lens frame disclosed in Patent Document 1 is provided with a through hole for inserting a screw on the outer peripheral side of the lens. Then, the lens frame is rotated in accordance with the adjustment position of the lens, and the lens frame is fixed by fixing screws at three positions at that position.

  However, in order to realize the lens movement adjustment method disclosed in Patent Document 1, it is necessary to provide screw holes for fixing the lens frame by the rotation angle necessary for the adjustment. Specifically, it is necessary to provide screw holes only at 120 degrees × 3 locations = 360 degrees. Therefore, in order to realize this lens movement adjustment method, it is necessary to secure a space on the outer periphery of the lens.

  It is also conceivable to fix the lens frame by bonding or the like instead of screws. However, even when the lens frame is fixed by bonding or the like, it is necessary to secure a space for bonding or the like only in a range in which the lens frame rotates. If you try to narrow the range in which the lens frame rotates in order to narrow the space for screw holes or space for bonding, etc., this will lead to a reduction in the number of adjustment step surfaces and lens adjustment The problem becomes insufficient.

  In other words, the conventional lens barrel requires a large space for fixing the lens frame on the outer periphery of the lens, and it is difficult to secure a space for arranging components other than the lens frame, such as a barrier unit. It was. In addition, it is necessary to increase the lens barrel diameter by the amount of components other than fixing the lens frame.

  An object of the present invention is to provide a lens barrel capable of adjusting the position of a lens frame with a simple structure and suppressing the space required for the position adjustment.

  A lens barrel according to an embodiment of the present invention is a lens barrel capable of adjusting the position of an adjustment lens included in a plurality of lenses of an optical system in the optical axis direction with respect to other lenses. The lens barrel includes a first holding frame that holds the adjustment lens and a second holding frame that holds the first holding frame in an adjustable manner. Either one of the first and second holding frames has a first adjustment surface having at least one adjustment surface provided at a different height adjacent to the rotation direction of the holding frame. A group and an adjustment surface group different from the first adjustment surface group, the second adjustment surface group including at least one adjustment surface provided adjacent to the rotation direction and having a different height. ing. The second adjustment surface group is provided at a 180-degree rotational phase position from the position where the first adjustment surface group is provided. Of the first and second holding frames, a holding frame different from the holding frame provided with the first adjustment surface group and the second adjustment surface group is the first adjustment surface group or the A support portion in contact with the second adjustment surface group is provided.

  According to the lens barrel of the present invention, it is possible to adjust the position of the lens frame with a simple structure and to reduce the space necessary for the position adjustment. Therefore, the outer peripheral space of the lens frame can be effectively used for other components.

It is a figure which shows an example of the disassembled perspective view of the lens-barrel of this embodiment. It is a figure which shows an example of the lens frame holding an adjustment lens. It is a figure which shows an example of the relationship between a base frame and an adjustment lens, and the cross section of a lens frame and a base frame. It is a figure explaining the change of the contact state of the adjustment surface and support surface at the time of tracking adjustment. It is a figure explaining the change of the contact state of the adjustment surface and support surface at the time of tracking adjustment.

  The lens barrel of this embodiment will be described below with reference to FIGS. FIG. 1 is a diagram illustrating an example of an exploded perspective view of a lens barrel of the present embodiment. FIG. 2 is a diagram illustrating an example of a lens frame that holds the adjustment lens. FIG. 3 is a diagram illustrating an example of a relationship between the base frame and the adjustment lens and cross sections of the lens frame and the base frame. The imaging apparatus of this embodiment includes a lens barrel of this embodiment described below.

  The lens barrel of the present embodiment can be obtained by moving the adjustment lens in the optical axis direction or tilting the optical axis of the adjustment lens with respect to the reference axis with respect to other lens groups (not shown) constituting the barrel. Adjust the position to satisfy the optical performance. That is, the lens barrel has a position adjustment structure in which the adjustment lens included in the plurality of lenses of the optical system can be adjusted with respect to other lenses in the optical axis direction. In the following description, adjustment by movement in the optical axis direction is described as tracking adjustment, and adjustment for tilting the optical axis of the adjustment lens with respect to the reference axis is described as tilt adjustment.

  FIG. 3A shows the relationship between the base frame and the adjustment lens. L1 is an adjustment lens whose position is adjusted. As shown in FIG. 3A, the adjustment lens L1 has a shape in which two side portions L1a and L1b in the vertical direction are cut from a round shape of φD. The lens frame 1 holds the adjustment lens L1 (a first holding frame).

  As shown in FIG. 2A, the lens frame 1 includes fixed arm portions 1a, 1b, 1c, and 1d, which are four fixing members extending in the radial direction, and has a 180-degree rotationally symmetric shape. The fixed arm portion is an arm for applying and fixing an adhesive to the fixed arm portions 1a, 1b, 1c, and 1d at a position where the adjustment lens is adjusted.

  Further, as shown in FIG. 2B, the first adjustment is made on the outer peripheral surface of the portion (holding portion) where the adjustment lens L1 is held in a state where the lens frame 1 holds the adjustment lens L1. A step surface 11 and a second adjustment step surface 12 are provided. The first adjustment step surface 11 functions as a first adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to each other in the rotational direction of the lens frame 1. In this example, the first adjustment step surface 11 has three adjustment surfaces 1e, 1f, and 1g. The respective adjustment surfaces of the first adjustment step surface 11 are arranged at different heights in accordance with the tracking adjustment width.

  The second adjustment step surface 12 functions as a second adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to the rotation direction of the lens frame 1. In this example, the second adjustment step surface 12 has three adjustment surfaces 1h, 1i, and 1j. The respective adjustment surfaces of the second adjustment step surface 12 are arranged with different heights according to the tracking adjustment width different from the tracking adjustment width of the first adjustment step surface 11. The second adjustment step surface 12 is provided at a 180 ° rotation phase position from the position where the first adjustment step surface 11 is provided.

  The base frame 2 holds the lens frame 1 so as to be adjustable (a second holding frame). When the base frame 2 is connected to a lens group (not shown) other than the adjustment lens L1, the lens barrel of the present embodiment is configured as a barrel composed of a plurality of lens groups.

  Three support surfaces 2a, 2b, and 2c are provided at 120 degrees equally on the inner periphery of the base frame 2. The support surfaces 2 a to 2 c support the lens frame 1 by contacting the first adjustment step surface 11 or the second adjustment step surface 12 of the lens frame 1.

  In the present embodiment, the lens frame 1, that is, the first holding frame includes the first adjustment step surface and the second adjustment step surface, but the base frame 2, that is, the second holding frame, instead of the lens frame 1, is the first. An adjustment step surface and a second adjustment step surface may be provided. In other words, one of the first and second holding frames includes a first adjustment surface group and a second adjustment surface group.

  The support surfaces 2a to 2c included in the base member shown in FIG. 3A function as support portions that come into contact with the first adjustment step surface or the second adjustment step surface 12 included in the lens frame 1. At least one of the support surfaces 2a to 2c (support surfaces 2a and 2b in this example) is provided at a position overlapping with the lens cut portions L1a and L1b of the adjustment lens L1 in the optical axis direction. As a result, the support surfaces 2a, 2b, and 2c need not be provided outside the outer diameter φD of the adjustment lens L1, and an increase in the size of the lens barrel can be suppressed.

  The cover member 3 has an opening provided at the center so as not to block the light beam that passes through the lens barrel and reaches the image sensor. The cover member 3 is provided on the subject side of the lens frame 1. The cover member 3 is fixed to the base frame 2 with screws 4.

  FIG. 3B is a diagram illustrating an example of a cross section of the lens frame and the base frame. With reference to FIG. 3B, the contact between the first adjustment step surface 11 or the second adjustment step surface 12 of the lens frame 1 and the support surfaces 2 a to 2 c of the base frame 2 will be described. In the following description, a mechanism in which the first adjustment surface 1f and the support surface 2a are in contact with each other will be described. However, the support surface is in contact with another adjustment surface by the same mechanism.

  By rotating the lens frame 1 by the widths of the three adjustment surfaces 1e, 1f, and 1g of the first adjustment step surface 11, the position of contact with the support surfaces 2a, 2b, and 2c of the base frame 2 sequentially changes. . As a result, the height of the adjustment lens L1 in the optical axis direction is changed, and tracking adjustment is performed.

  Further, the adjustment surfaces 1e, 1f, and 1g are formed in an R surface shape from a predetermined reference position. Accordingly, when the adjustment surface is brought into contact with the support surfaces 2a, 2b, and 2c of the base frame 2 formed of a flat inclined surface, the optical axis O can be inclined on R around a predetermined reference position. As a result, tilt adjustment is possible. In order to stably support the lens frame 1, the support surfaces are provided at three positions equal to 120 degrees, but need not necessarily be equal to 120 degrees.

  In this example, the base frame 2 has a support surface. However, the base frame 2 may include a first adjustment step surface and a second adjustment step surface, and the lens frame 1 may include a support surface. That is, of the first and second holding frames, the holding frame different from the holding frame provided with the first adjustment step surface and the second adjustment step surface is the first adjustment step surface or the second adjustment step surface. And a support portion that abuts.

  5 and 6 are diagrams for explaining changes in the contact state between the adjustment surface and the support surface during tracking adjustment. FIG. 5A shows a state in which the adjustment surface 1e and the support surfaces 2a, 2b, and 2c are in contact with each other. FIG. 5B shows a state where the adjustment surface 1f and the support surfaces 2a, 2b, and 2c are in contact with each other. FIG. 6 shows a state in which the adjustment surface 1g and the support surfaces 2a, 2b, and 2c are in contact with each other.

  The lens frame 1 that has been subjected to tracking adjustment and tilt adjustment is fixed to the base frame 2 by adhesion. Here, if the adhesive is set to be applied in the range of 2d, 2e, 2f, and 2g shown in FIGS. 5 (A) to 6, any state shown in FIGS. 5 (A) to 6 will be described. However, the adhesive is surely applied on the fixed arm portions 1a, 1b, 1c, and 1d. Thereby, the lens frame 1 can be reliably fixed to the base frame 2.

  The adhesive application ranges 2d, 2e, and 2f are determined by the width of the fixed arm and the amount of rotation of the lens frame 1 used for tracking adjustment. That is, the lens frame 1 and the base frame 2 are fixed by a fixed arm portion to which an adhesive is applied. In the present embodiment, adhesive grooves 1k and 1l are provided in the lens frame 1 by using portions corresponding to the L1a and L1b portions cut from the arc of the adjustment lens L1, and the base frame 2 is bonded and fixed.

  The application range of the adhesive to the fixed arm portion is a range determined based on the width of the fixed arm portion in the rotation direction and the rotation amount of the lens frame 1 necessary for tracking adjustment. If the rotation amount of the lens frame 1 for tracking adjustment is reduced, the application range of the adhesive can be narrowed accordingly.

  The lens frame 1 is provided with a second adjustment step surface 12, and the second adjustment step surface 12 and the support surfaces 2a, 2b, and 2c can be brought into contact with each other. As described above, the second adjustment step surface 12 is provided at the 180-degree rotational phase position of the first adjustment step surface. That is, when the lens frame 1 is rotated 180 degrees and placed on the base frame 2 from the state in which the first adjustment step surface 11 is in contact with the support surface, the second adjustment step surface 12 is in contact with the support surface.

  That is, the support surface provided in the holding frame different from the holding frame provided with the first adjustment step surface and the second adjustment step surface comes into contact with the second adjustment step surface in the following cases. In other words, the support surface is configured such that the holding frame provided with the first adjustment step surface and the second adjustment step surface moves the support surface at a rotational phase position of 180 degrees from the position where the support surface contacts the first adjustment step surface. When placed on the holding frame provided, it comes into contact with the second adjustment step surface.

  Since the second adjustment step surface 12 is provided with a height different from that of the first adjustment step surface 11, tracking adjustment can be performed at a height position that cannot be adjusted by the height of the first adjustment step surface. It becomes possible.

  Further, the fixed arm portions 1a, 1b, 1c, and 1d of the lens frame 1 have a shape made to be 180 degrees rotationally symmetric. Specifically, the fixed arm portion 1a and the fixed arm portion 1c are provided at a 180 ° rotation phase position. The fixed arm portion 1b and the fixed arm portion 1d are provided at a 180 ° rotation phase position. Therefore, even when tracking adjustment is performed using the second adjustment step surface 12, if the adhesive application range for fixing the lens frame 1 is set to 2d, 2e, 2f, and 2g shown in FIG. The frame 1 can be securely fixed to the base frame 2.

  In the configuration in which the adjustment surface is provided on the base frame 2 instead of the lens frame 1 and the support surface is provided on the lens frame 1, the base frame 2 may be provided with a fixed arm portion. That is, of the first and second holding frames, the holding frame is provided on the outer periphery of the holding frame provided with the first adjustment step surface and the second adjustment step surface with respect to the holding frame having the support surface. A plurality of fixed arm portions to be fixed are provided. Each fixed arm portion included in the plurality of fixed arm portions is provided at a 180 ° rotation phase position with respect to the corresponding fixed arm portion.

  According to the above configuration, the lens frame 1 can be adjusted within the first adjustment step surface by rotating the lens frame 1, and the lens frame 1 can be further rotated 180 degrees with respect to the base frame 2 in the second adjustment step surface. But it is adjustable. In other words, the position adjustment mechanism can be adjusted with the number of adjustment steps corresponding to two of the first adjustment step surface and the second adjustment step surface, with only the lens frame rotation angle corresponding to the number of steps where the first adjustment step surface is installed. .

  Specifically, the height of the first adjustment step surface 11 can be adjusted by three steps, and the second adjustment step surface 12 can be adjusted by three steps at a different height. That is, according to the lens barrel of the present embodiment, height adjustment for six steps can be performed while suppressing the rotation angle of the lens frame 1 rotated for adjustment.

  When the rotation angle of the lens frame 1 is small, the rotation range of the fixed arm portions 1a, 1b, 1c, and 1d for fixing the lens frame 1 is reduced. As a result, the ranges 2d, 2e, 2f and 2g where the adhesive is applied are narrowed. If the adhesive application range can be made small, the space on the outer periphery of the adjustment lens L1 can be used for components other than the adhesive.

  In the present embodiment, screw fastening seats 2h and 2i for fixing the cover part 4 are provided in the space on the outer peripheral portion of the adjustment lens L1. The outer peripheral space is used as a space for inserting a component such as a barrier device that protects the lens from being damaged when the lens barrel is housed or a part of a component that is arranged closer to the image sensor than the lens frame 1. It is possible to effectively use the space. Thereby, size reduction of a lens-barrel can be achieved.

  According to the present embodiment described above, the position of the lens frame 1 can be adjusted by rotating the lens frame 1, and the position of the lens frame 1 can be adjusted by rotating the lens frame by half the number of adjustable steps. Can do. Thereby, size reduction of a lens-barrel is implement | achieved.

  The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention. For example, the number of adjustment surfaces of the first adjustment step surface 11 and the second adjustment step surface 12 may be different. May be the same.

  In the above-described example, the adjustment lens L1 has a configuration capable of tracking adjustment and tilt adjustment, and the first adjustment step surface has an R shape. However, the adjustment lens L1 may be capable of only tracking adjustment. And the 1st adjustment step surface may be comprised by the flat surface.

  In the above-described example, the adjustment lens L1 has a lens shape in which portions L1a and L1b of the φD arc are cut. However, the adjustment lens L1 is not limited to this, and may be a round shape or further in the left-right direction. The cut shape may be sufficient.

1 Lens frame 2 Base frame

Claims (5)

A lens barrel that adjusts the position of an adjustment lens included in a plurality of lenses of an optical system in the optical axis direction with respect to another lens,
A first holding frame for holding the adjustment lens;
A second holding frame that adjustably holds the first holding frame;
One of the first and second holding frames has a first adjustment surface group having a plurality of adjustment surfaces provided with different heights adjacent to the rotation direction of the holding frame. And an adjustment surface group different from the first adjustment surface group, and a second adjustment surface group consisting of a plurality of adjustment surfaces provided at different heights adjacent to each other in the rotational direction. ,
The second adjustment surface group is provided at a 180-degree rotational phase position from the position where the first adjustment surface group is provided,
Of the first and second holding frames, a holding frame different from the holding frame provided with the first adjustment surface group and the second adjustment surface group is the first adjustment surface group or the second adjustment frame. A lens barrel comprising a support portion that contacts the adjustment surface group. Of the first and second holding frames, the support portion provided in a holding frame different from the holding frame provided with the first adjustment surface group and the second adjustment surface group is the first adjustment surface. A holding frame provided with a group and the second adjustment surface group is placed on the holding frame provided with the support portion at a rotation phase position of 180 degrees from a position where the support portion comes into contact with the first adjustment surface group. The lens barrel according to claim 1, wherein the lens barrel comes into contact with the second adjustment surface group. Of the first and second holding frames, the holding frame is provided with the holding frame on the outer periphery of the holding frame provided with the first adjustment surface group and the second adjustment surface group. There are provided a plurality of fixing members that are fixed to
The lens barrel according to claim 1, wherein each of the plurality of fixing members included in the plurality is provided at a 180-degree rotational phase position with respect to the corresponding fixing member. The first holding frame and the second holding frame are fixed by the fixing member to which an adhesive is applied,
The application range of the adhesive to the fixing member is a range determined based on the width in the rotation direction of the fixing member and the amount of rotation necessary for the position adjustment of the holding frame including the fixing member. The lens barrel according to any one of claims 1 to 3.   An imaging device comprising the lens barrel according to any one of claims 1 to 4.

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